“OK boomer.” VSCO girls. “Old Town Road.” Even if you’re not on TikTok, you’re probably familiar with some of its most pervasive memes. TikTok, or Douyin, as it’s known in China, is a social network where users share short videos, typically set to music. Launched in its current form when China-based TikTok merged with lip-syncing app Musical.ly in 2018, the app has rapidly skyrocketed to cultural dominance. Downloaded 2 billion times, TikTok has 700 million monthly active users worldwide, including 100 million active users in the U.S.—up 800% in just over two years. Among Gen Z, it’s ubiquitous: About 40%